The present invention relates to manufacturing control technology and in particular to a method for estimating manufacturing target bias.
In high-technology manufacturer, such as in integrated circuit (IC) product manufacturer, before quantity production, testing operation for products must be executed, that is a pilot run, for examination. An important object of the testing operation is acquisition of a manufacturing target bias for the product. Manufacturing target bias accommodates hardware limitations of manufacturing tools. For example, if a target width of an IC product is 130 nanometers, and testing operations in a specific manufacturing tool show 132 nanometers, thus, a manufacturing target bias is designated as 2 nanometers for the tool, which is then applied in the specific tool for ongoing production.
Accurate manufacturing target bias is an essential requirement for product manufacturing, especially for non-reworkable manufacturing tools. In a non-reworkable manufacturing tool, the manufacturing process operated therein cannot be repeated, such as etching. Conventionally, manufacturing target bias must be established for each tool even tools operating in the same manufacturing conditions, i.e. using the same recipe for the same IC product. Manual preparations must take place before ongoing production, a time-consuming and human resource intensive requirement.
FIG. 1 is a diagram of a pilot run in IC product manufacture, in which, three specific etching tools use the same recipe for an IC product, and each manufacturing tool has three chambers. The product, accordingly, must undergo a pilot run in each tool and each chamber to generate manufacturing target bias, a total of nine trials. Generally, the number of the manufacturing tools in an IC product manufacturing factory is large, such that the pilot runs for a product entail a complicated process.
U.S. Pat. No. 6,480,794 discloses a method for allocating products to be tested to machines on a manufacturing line, providing a standard test time with minimized total test time, forming a supply demand matrix table for products and machines to which the products are to be allocated, determining the grid location with a minimum testing time Tij. The method does not disclose estimation of manufacturing target bias, despite utilizing a pilot run. Other inventions are concerned with specific manufacturing processes, such as U.S. Pat. No. 6,514,673, which discloses a simple method for calculating the optimum amount of HDP deposited material to be removed during CMP (without introducing dishing), but, is not applicable to the mentioned manufacturing target bias estimation problem.